<template>
  <div class="channel-edit">
    <van-cell :border="false">
      <div slot="title" class="title-text">我的频道</div>
      <van-button 
      class="edit-btn" 
      size="mini" 
      round type="danger" 
      plain
      @click="isEdit = !isEdit"
      >{{ isEdit ? '已完成' : '编辑' }}
      </van-button>
    </van-cell>
    <van-grid class="my-grid" :gutter="10">
      <van-grid-item
        class="grid-item"
        v-for="(channel, index) in myChannels"
        :key="index"
        @click="onMyChannelClick(channel, index)"
      >
     <van-icon 
     v-show="isEdit && !fiexdChannels.includes(channel.id)" 
     slot="icon" 
     name="clear">
     </van-icon>
       <span class="text" :class="{ active: index === activeIndex }" slot="text">{{ channel.name }}</span>
      </van-grid-item>
    </van-grid>
    <van-cell :border="false">
      <div slot="title" class="title-text">频道推荐</div>
    </van-cell>
    <van-grid class="recomment-grid" :gutter="10">
      <van-grid-item
        icon="plus"
        class="grid-item"
        v-for="channel in recommendChannele"
        :key="channel.id"
        :text="channel.name"
        @click="onAddChannel(channel)"
      />
    </van-grid>
  </div>
</template>

<script>
import {
  getAllChannels, 
  addUserChannel,
  deleteUserChannel
} from '@/api/channel.js'
import { mapState } from 'vuex'
import { setItem } from '@/utils/storage.js'
export default {
  name: 'ChannelEdit',
  data () {
    return {
      allChannels: [], // 所有的频道
      isEdit: false, // 插插按钮的变量
      fiexdChannels: [0] // 不需要编辑、删除的频道
    }
  },
  props: {
    myChannels: {
      type: Array,
      required: true
    },
    activeIndex: {
      type: Number,
      required: true
    }
  },
  created () {
    this.loadAllChannels()
  },
  methods: {
    // 添加频道
    async onAddChannel (channel) {
      this.myChannels.push(channel)
      // 数据持久化处理
      if (this.user) {
        // 已登录，把数据请求接口放到服务器
        try {
          await addUserChannel({
            id: channel.id, // 频道 ID
            seq: this.myChannels.length // 序号
          })
        } catch (error) {
          this.$toast('保存失败，请稍后再试')
        }
      } else {
        // 未登录，把数据存储到本地
        setItem('TOUTIAO_CHANNELS', this.myChannels)
        // console.log('储存成功')
      }
    },
    async loadAllChannels () {
      try {
        const { data } = await getAllChannels()
        this.allChannels = data.data.channels
        // console.log(data.data.channels)
      } catch (error) {
        // console.log(error)
        this.$toast('获取所有频道数据失败')
      }
    },
    onMyChannelClick (channel, index){
      if (this.isEdit) {
        // 在fiexdChannels的数据无法往下执行
        if (this.fiexdChannels.includes(channel.id)){
          return
        }
        // 编辑状态
        // 删除被点击的数据
        this.myChannels.splice(index, 1)

        if (index <= this.activeIndex){
          this.$emit('update-active', this.activeIndex - 1, true)
          // console.log('111', this.activeIndex)
        }
        // 处理持久化操作
        this.deleteChannel(channel)
      } else {
        // 非编辑状态,指向切换频道
        this.$emit('update-active', index, false)
      }
    },
    // 删除频道
    async deleteChannel (channel) {
      try {
        if (this.user) {
          await deleteUserChannel(channel.id)
          // console.log(channel.id)
        } else {
          // 未登录，将数据更新到本地
          setItem('TOUTIAO_CHANNELS', this.myChannels)
        }
      } catch (error) {
        this.$toast('操作失败，请稍后重试')
      }
    }
  },
  computed: {
    recommendChannele () {
      // 数组的 filter 方法：遍历数组，把符合条件的元素存储到新数组中
      return this.allChannels.filter(channel => {
      // const channel = []
      // 数组的 find 方法：遍历数组，把符合条件的第一个元素返回
        return !this.myChannels.find(myChannel => {
          return myChannel.id === channel.id
        })
      })
    },
    ...mapState(['user']),
  }
}
</script>

<style scoped lang="less">
.channel-edit {
  padding: 85px 0;

  .title-text {
    font-size: 32px;
    color: #333;
  }

  .edit-btn {
    width: 104px;
    height: 48px;
    font-size: 26px;
    color: #f85959;
    border: 1px solid #f85959;
  }

  /deep/ .grid-item {
    width: 160px;
    height: 86px;
    .van-grid-item__content {
      white-space: nowrap;
      background-color: #f4f5f6;

      .van-grid-item__text {
        font-size: 22px;
        color: #222;
        margin-top: 4px !important;
      }
    }
  }

  /deep/ .my-grid {
    .grid-item {
      .van-icon-clear {
        position: absolute;
        right: -10px;
        top: -10px;
        font-size: 30px;
        color: #cacaca;
        z-index: 2;
      }
    }
  }

  /deep/ .recomment-grid {
    .grid-item {
      width: 160px;
      height: 86px;
      .van-grid-item__content {
        flex-direction: row;
        .van-icon-plus {
          font-size: 22px;
          line-height: 22px;
          margin-right: 6px;
        }
      }
    }
  }
  .van-grid-item__text, .text {
    font-size: 22px;
    color: #222;
    margin-top: 4px !important;
  }
  /deep/ .grid-item {
    width: 160px;
    height: 86px;
    .van-grid-item__content {
      white-space: nowrap;
      background-color: #f4f5f6;
      .van-grid-item__text, .text {
        font-size: 22px;
        color: #222;
        margin-top: 4px !important;
      }
      .active {
        color: red;
      }
      .van-grid-item__icon-wrapper{
        position: unset;
      }
    }
  }
}
</style>
